Conventionally, there is known technology for coating the surface of a web with powder while conveying the web.
For example, JP 2011-216504 A discloses technology for coating the surface of a collector (the web) as a long metal sheet with composite material (the powder) containing active material.
In the technology described in JP 2011-216504 A, the thickness of the coated powder is evenly adjusted by smoothing the powder with a blade-shaped squeegee after supplying the powder to the surface of the web (see paragraph [0047] in JP 2011-216504 A).
However, as shown in FIG. 5, when the powder comes in contact with the squeegee, the powder receives the force acting in the opposite direction of the moving direction thereof (in the conveying direction of the web), and therefore the powder may stay (a bridge may be formed) on the upstream side in the conveying direction of the web relative to the squeegee.
Therefore, it is difficult to evenly smooth the powder supplied to the surface of the web by the technology described in JP 2011-216504 A.
The white-painted arrow in FIG. 5 indicates the conveying direction of the web.